3 o4 
Ward . — Some Thames Bacteria. 
depend on the temperature. Fig. 14 gives a case where the 
single rodlet at 10.25 p.m. had divided at 11 p.m., and the 
two halves separated at 11.5 p.m. : these two oscillated away 
from and towards one another as above described, and 
went on doing this and dividing through the night, and at 
7 next morning had developed into a colony about 25 \x in 
diameter, and containing probably 10,000 to 15.000 of the 
short rodlets, all swarming actively, in the circumscribed 
space of their own gelatinous investment. 
If the temperature does not rise beyond about 20° the 
colonies are developed without any swarming. Thus Fig. 15 
shows a case where a rodlet was fixed at 4 p.m. in io°/ o 
gelatine and remained at 15 0 C. through the night. Next 
morning at 8-i 5 it had formed a small colony about 3 m in 
diameter, and consisting of eight to ten rodlets, so far as 
I could make out — possibly twelve. The temperature was 
then allowed slowly to rise to 20-25° C., and at 3 p.m. the 
lobed colony of quiescent short rodlets and 1 5-16// in 
diameter, shown in Fig. 15 (c), had formed. At 8.30 p.m. 
the whole colony was in active swarming, but next morning 
was quiescent again. 
Numerous attempts to cultivate this form further were 
made without success. 
III. Rose-pink Micrococcus : Type of M. carneus . (Zimm.) 
(PL XXI.) 
A very pretty rose-pink form was isolated several times 
and studied during the winter of 1894-95, when it seemed 
fairly common. It is by no means one of the more frequent 
forms in the Thames, however. I was for some time puzzled 
by it, for at one period its alliances seemed doubtful. It 
occurs as spherical cocci of variable sizes, from 0-5 to i*o ju, 
or even occasionally up to 1 • 5 /x or nearly so, in diameter, 
in irregular botryoidal groups, and perfectly quiescent. 
It stains easily, and well-stained specimens may show 
a darker more or less central spot, and a paler halo round 
